Thermoelectric generating system



June 5, 1945. w. A. RAY 2,377,516

' THERMOELECTRIC GENERATING SYSTEM- Original Filed Jan. 15, 1941 MLL/AM,4. FAY

;n z a;

(Ittorneg Patented June 5, 1945 2,377,516 THERMOELECTRIC GENERATINGSYSTEM William A. Ray, Los Angeles, Calif.

Original appllcation January 13.1941, Serial No. 374,303, now Patent No.2,288,300, dated June 30, 1942. Divided and this application May 19,1942, Serial No. 443,608

1 Claim. 7 (Cl. 136-4) This invention relates to control systems whichinclude thermoelectric generating means, the present application being adivision of my copending application, Serial No. 374,303, flied January13, 1941; vnow Patent No. 2,288,300, dated June 30, 1942.

In some control systems, a source of direct current at very low voltageis desirable, one of the advantages of the use of such current being thesubstantial elimination of arcing at contacts for controlling thecurrent, so that condition responsive control devices of the simplefloating or non-snap-action type may be employed; further advantagesbeing pointed out in my U. S. Patent No. 2,274,938 for Control circuit.It is therefore an object of this invention to provide means forgenerating such energy thermoelectrically and as an incident to theenergization of an ordinary electrically operated device, such as amotor, relay or the like; or, more specifically, the provision of athermoelectric device so arranged as to be influenced to generateelectricity-by the passage of current through the coil winding of suchan ordinary electrically operated device.

Another object is the provision of thermoelectrio-means constructed andarranged to be iniiuenced to generate electricity by the flux producedby alternating current flow in an ordinary electrically operated device.

One of the inherent advantages of this invention resides in the factthat, by so arranging the thermoelectric means, the generation ofthermoelectricity ceases when the electrically operated device withwhich it is associated is unen'ergized; the load normally energized bythe thermoelectricity then being restored to an unenergized "safe"condition,

Other objects and advantagesof the invention will be found in thedescription, the drawing and the appended claim; and for completeunderstanding of the invention reference may be had to the followingdetailed description and accompanying drawing, wherein:

Figure 1 is a diagrammatic view of one form of thermoelectric devicewhich is adapted for use in the system of my invention; and

. v Figure 2 is a. diagram ofa system according to my invention whereinthe device shown. in Fig. 1 is employed.

Referring first to Fig. 1, the thermocouple ring" or bridge" showntherein comprises a plurality of pairs of thermocouple elements ii andi2,.oi dissimilar metals or alloys, interconnected at their coldjunction ends by relatively conductivity and low electrical resistance,such as copper. If a source of alternating current is connected topoints of the ring about which the numbers of pairs of thermocoupleelements are equally arranged, the alternating current passes equallythrough the parallel branches of the ,ring and thus heats thethermocouple elements II and I! which offer considerably greaterresistance to cur-- rent flow, on account of their smaller size andgreater specific resistance, than do the copper elements i3. Theelements II and i2 may preferably be of such alloys as Copel andChromel,"

- respectively. The adJoining ends, or hot Junetions, of elements Ii andI! are thus at a higher temperature than the opposite, or cold junction,ends of these elements which are connected to the relatively cool copperelements It, and consequently current is generated which tends to flowin the direction of the arrows, element l2 connected to the directcurrent output leads,

whereupon the generated current flows equally through the right and lefthand portions of the ring, as indicated by the arrows. Any even numberof pairs of thermocouples may be provided in these portions as long asthe proper alternatin curemt and direct current balances are maintained.

In Fig. 2, the numeral l6 indicates an ordinary A. C. operated device,such as a motor or relay, having a core l8 and an energizing coilwinding i1 around one portion thereof. Around another portion of thecore is a winding l8 consisting of a thermocouple ring similar to thatshown in Fig. 1. In this arrangement, the alternating current forheating the theme-Junctions, instead of being supplied directly to thering, is electromagnetically induced'therein by the alternating fluxpro.

duced in the core. The parallel sections of the ring shown in Fig. 1form a double winding around the core so that there is the same balancedA. C. eflect with respect to the D. C. connections as in Fig. 1. Thewire it corresponds to the A. C.

massive elements It of metal having high heat supply leads of Fig. 1 andis connected to the same points of the ring as are those leads. The E.M. F. induced in both sections of the double winding i8 is always thesame in direction and magnitude and hence A. C. flows through both ofthese sections, in parallel, in series with wire IS; the A. C. circuitthus being eflectively the same as in Fig. l. The D. C. load isconnected to the midpoints of the. winding sections, which mid-pointsare constantly at the same alternating potential due to the equaldistribution of electrical resistance at opposite sides or themid-points, and hence no A, C. can flow to the load; further, no D. C.can flow in wire l9 since it is connected at points of the D. C. circuitof equal and opposite potential.

I claim as my invention:

In a, thermoelectric generating system: an electromagnetic device,adapted to be operated by alternatingv current, comprising a, core anda. coil for energizing the same: a pair of windings around said core andJoined together in parallel at their respective ends. and separateconducting mean interconnecting said ends: said windings being soarranged that, when said core is energized, alternating current isinduced constantly in thesame direction and magnitude in each of theparallel windings; a pair of thermocouples connected in series in eachof said windings, one thermocouple at either side of the mid-point ofthe winding, the individual thermocouples of each pair being in opposedrelation to each other; each oi said thermocouples comprising a. pair ofdissimilar elements joined together at one end to form a hot-junction;the cross-sectional area oi said elements being smaller than that of theportions of the windings to which the other or cold-Junction ends of thethermocouples are connected, so that the hot-junctions are heated to a.higher degree than the cold-junctions by passage of said inducedcurrent, and thereby direct current is enerated; and electricalconnections for said direct current made at said mid-points of thewindings; said thermocouples being so oriented that the generated directcurrent will flow from either side of one of the windings toward itsrespective mid-point, and toward either side of the other of thewindings from its respective mid-point; the distribution of electricalresistance through eachof the windings, and the thermocouples therein,being such that said midpoints are constantly at the same alternatingpotential.

WILLIAM A. RAY.

